Little Snitch: Keep Apps In Line

While Mac OS X does provide a firewall, it is not rules based so it does not allow as fine control over who and what accesses your network connection. Little Snitch from Objective Development does just this - it adds rule based protection for your Mac. As a rules based firewall, Little Snitch is not a replacement for the OSX firewall, it just provides program level (instead of IP and port level) control over your outgoing network traffic.

Little Snitch lives in the System Preferences panel and whenever an app tries to access your network/internet connection, it notifies you and asks you what you want it to do. You can either permanently or temporarily (until the app closes) allow or block an app as well as fine tune the conditions to allow the app to connect to any server, or only to the specified port or IP address.

In the Little Snitch Preferences Panel, you can see all the rules that have been created (including the default ones allowing important system processes to connect) and their conditions. Here you can also modify or delete existing rules or manually add rules. Manually added rules allow you to define an application and its permission (allow or deny), server (IP address or domain), port, and protocol. You can also change these settings for any previously created rule.

If you want to know who and what are accessing your network connection, want to prevent certain apps from “phoning home,” or are just paranoid, Little Snitch is for you. It is a shareware app and costs $24.95 for a one seat license.